please help..Mission 753 tweeter stopped working after mod

[satz]

Dear all

have a pair of original Mission 753 which were working perfectly.

But I tried to do the usual tweeter-grill removal mod.

Seemed to go okay, but I noticed the fine copper wire around the tweeter came a bit loose. It doesn't seem broken though.

When I reassembled everything the tweeter doesn't work at all 🙁

I've tried reassembling several times, but no luck.

Does the copper wire need to be fully wound around the tweeter edge or is some of the wire meant to go into the groove in the 'base' (where the foam plug has a groove around it)?

I hope someone can help please...

 

[AllenB]

Hmm, that doesn't look good. Is it just me or is that coil deformed?

 

[satz]

hi Allen
yes, unfortunately the coil and the edge of the tweeter seem deformed. Approx 50% of the coils seem to be sitting correctly, but the rest is loose.

I think the damage to the edge of the tweeter (metal bit) could be from me trying to reassemble it onto the magnet base?
cheers

 

[AllenB]

Firstly, if it doesn't work then measuring resistance may possibly show the coil has opened. Even still, since it is a precision device you might not expect to return original performance by bending it back into shape or by forcing it into place. Thirdly if it is not attached securely it won't work properly and fourth, the former is damaged and its rigidity could be compromised.

Can you replace it?

 

[VaNarn]

Unfortunately that is a damaged coil and if you cannot get a replacement diaphragm assembly or a complete tweeter, then a another maker's dome tweeter will have to be adapted for the Mission 753.

 

[stoolpigeon]

That tweeter has been transformed to a condition that begins with f and ends with ed.

sp

 

[system7]

Looks wrecked to me.

Replacement might be hard in your region, but it might be a scanspeak voiceoil of some sort:

Scanspeak Discovery Voice Coil for D2608/9130

Or fit a new vaguely similar unit:

Monacor DT-75 Size 93x69mm

Usually not hard to adjust resistor level on what is probably a three element tweeter filter.

 

[satz]

hi all, I think yes it needs to be replaced.

Has anyone done the Willys-Hifi replacement tweeter option? That seems to be a direct replacement, except that it's a silk-dome rather than the metallic one.

What would that do to the overall sound?

cheers

 

[MAAC0]

Measure the voice coil. If it's not open You can try to glue the coil to the former with nail laquer or some sort of veneer. Make sure it sits flush and doesn't rub in the gap. Use a toothpick and steady hands to put it in place while gluing.

 

[satz]

Hi Maaco, I will give that a try. Thank you.

Do you know if there's any simple way to test the tweeter before I refit it to the main speaker itself?